As far as we know, this off-road driver is careful not to run wild, trampling tender vegetation or ruining others' visual experiences. But not everyone is considerate.

Visitors from all over the world come to the United States to see for themselves the vastness of the American countryside and its incredible natural wonders - particularly out West.

The US Bureau of Land Management alone looks after 107 million hectares of American wilderness, including some of the most spectacular scenery in the world.

You can see why the sheer walls of the Devil's Tower in Wyoming is a magnet for rock climbers. But some ignore requests to avoid the area during Sioux Indians' sacred ceremonies at the site.

The National Park Service oversees still more popular attractions such as Yellowstone National Park in the West and the Great Smoky Mountains back east. The park service has more than one-and-one-half times more land to manage than it did 30 years ago, but 20 percent FEWER rangers to do it with. The same story applies to the US Forest Service.

Add to the mix the tremendous increase in visitors, especially eco-tourists and people on outdoor-adventure vacations, and rangers face real problems.

Distinctive sahuaro cacti grow in profusion in only one place: southern Arizona. They're a treat to see, but some thoughtless jerks use them for target practice and blast holes in them.

People on dirt bikes, dunebuggies, and snowmobiles are taking off into what used to be wild back country to escape city life and get a taste of nature in the raw. Not only does this increase dangerous contact with animals and disrupt their habitat, it also tears up fragile ecosystems like the dunes and desert flora.

There are thieves and vandals out there, too, and fewer rangers to catch them. Punks who think it's funny to spray-paint a national monument, for instance, break off cave formations, or steal sacred arrowheads to take home as souvenirs.

In Wyoming, inconsiderate people climb the sheer walls of the Devil's Tower National Monument - which was featured in the movie Close Encounters of the Third Kind - right in the middle of sacred ceremonies of the Lakota Sioux Indian tribe.

Catching vandals and illegal hunters and thieves with fewer and fewer rangers is a difficult task that makes one appreciate, all the more, the unspoiled natural beauty that remains.

dunebuggy: 沙滩车

snowmobile: a motor vehicle that can move over snow and ice easily（机动雪橇；雪地机动车）

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（来源：VOA 编辑：陈丹妮）